The present invention relates to a recording and reproducing apparatus and a recording method.
These years, when audio data is recorded on a recording medium such as a compact disc (CD), the audio data is subjected to compression-coding to reduce the data amount before being recorded on the recording medium. This saves the memory space of the recording medium.
When reproduced, the compressed audio data read out from the recording medium is first stored in reproduction memory. The compressed audio data is then read out from the reproduction memory and decompression-decoded, so that the original audio data is reconstructed and output.
This type of apparatus, during the reproduction of the audio data, responds to a user instruction by clipping out part of the compressed audio data stored in the reproduction memory and recording the clipped compressed audio data in recording memory as well.
Then, according to a user instruction, the apparatus reads out the clipped compressed audio data from the recording memory to decompression-decode it and output it. This allows the user to use desired part of the audio data as, for example, alarm data for wake-up.
When the apparatus clips out part of the compressed audio data stored in the reproduction memory and records the clipped compressed audio data in the recording memory by copying it to the recording memory, the apparatus records the clipped compressed audio data in sectors, which are the units used for reading out the compressed audio data from the recording medium.
On the other hand, when the apparatus reads out the clipped compressed audio data from the recording memory and decompression-decodes the clipped compressed audio data, the apparatus performs the decompression decoding in blocks, which are the units used for the compression coding of the audio data. That is, the apparatus requires the compressed audio data for at least one block when performing the decompression decoding: the apparatus cannot decompression-decode those data parts that contain compressed audio data for less than one block.
Since a sector and a block differ in size (data length), the boundaries between adjacent sectors and the boundaries between adjacent blocks in the compressed audio data do not align with each other. For example, the block size may be larger than the sector size.
Therefore, when sectors constituting the compressed audio data intended for recording are recorded in the recording memory, there may be a case where a recorded block expanding over the first sector intended for recording and its immediately preceding and following sectors lacks data for the first part of the block. Then, this block cannot be decompression-decoded.
Thus, there has been a problem that, although a sector consisting of only part of a block incapable of decompression decoding is recorded in the recording memory, the block recorded for that sector cannot be decompression-decoded, and the memory capacity of the recording memory is wasted.
A document related to an optical disc apparatus is listed below.
Japanese Patent Laid-Open No. 2003-331524